Chinese regulators are investigating a Wal-Mart store in the city of Shenzhen following the release of a video showing alleged food violations.

The video, which was allegedly filmed and narrated by a Wal-Mart employee, shows footage of worms crawling on rice and frying oil so old that it's "black as soy sauce," Reuters reports.

The narrator claims that Wal-Mart employees use the old oil to fry meat that is sold to customers and routinely used chicken that had passed it's sell-by date, according to the Wall Street Journal.

Wal-Mart launched an investigation following the release of the video and said it found no evidence of any food safety violations.

"We also have cooperated fully with [local authorities] to probe into the case," the company said in a statement. "If we find any violation, we will take immediate actions to redress it."

Chinese authorities have taken samples of oil and meat for testing.

The video's release follows a recent investigation into a Chinese meat supplier that found it had been selling expired meat to a number of U.S. companies, such as McDonald's and Yum Brands, which owns Pizza Hut and KFC.

A separate investigation earlier this year found that the donkey meat sold at some Wal-Mart stores in China contained the DNA of foxes. The company was forced to recall the meat, which came from a local supplier.